This invention relates to a connection portion of a contact for use in an electrical part, such as, an electrical connector.
Inside an electrical part, for example, an electrical connector, there are provided contacts made of worked metal pieces, each having on the one hand a connection portion in the form of a substantially U-shaped groove formed by bent parts of the contact, to which is connected an exposed conductor of an electric wire by soldering or solderless joining and on the other hand a contact portion adapted to be in contact with a contact of a mating connector.
These contacts have been produced in various methods. With miniaturization of electrical connectors themselves and high density distribution of contacts in electrical connectors, the contacts themselves have also been required to be miniaturized. Under such circumstances, a great number of contacts have been continuously produced in mass production by punching a long metal tape or a wide metal sheet of, for example, copper, and then by bending the punched blank pieces. Such a production method is high in productivity making it possible to reduce the cost per contact.
In the connection portion of a hitherto used contact, which is in the form of a substantially U-shaped groove, extension pieces are bent to form the walls of the U-shaped groove for enclosing an exposed conductor of an electric wire in order to connect it to the connection portion of the contact. However, the extension pieces prior to being bent are in general rectangular (or square), which are the same in shape and arranged on both sides of and symmetrically with respect to the longitudinal axis of the contact. In the case that the contacts themselves are miniaturized and produced in mass production, it is needed to make minimum the pitch between the contacts so that the extension pieces forming the walls of connection portions of the contacts need to have narrower widths in the direction perpendicular to the longitudinal axis of the contacts.
In this case, however, such narrower widths of the extension pieces could not provide a groove-shaped connection portion having a sufficient depth or width. Such a connection portion having a shallow or narrow groove does not effectively enclose an exposed conductor of an electric wire and makes it impossible to apply a sufficient amount of solder in soldering or cannot achieve a sufficient strength at the solderless joint.
If the widths of extension pieces of the contact are made wider, it may be possible to overcome these problems. However, such wider extension pieces make larger the pitch between contacts in a metal tape or sheet to lower the yield or productivity so that a great amount of waste material could not be avoided.